The purpose of this continuing project is the development and clinical implementation of a generalized system for external beam treatment planning. It will enable the optimum utilization of existing treatment facilities. The system is based on a generalized 3-D dose field model which covers photon and electron as well as neutron beams. The computer program and most of its clinical implementation was completed for the photon and electron fields available form the local Clinac 4, Clinac 8 and Clinac 20 linear accelerators. More work is to be done on the implementation of the Microtron with its 2 photon energies and 9 electron enegies and some unusual technical options. The current capabilities include interactive simulation of most irradiation techniques, including the effect of most beam modifying devices. Transverse patient contours are overlaid on corresponding CT scans so that dose distribution can be related to the anatomy. Three of the four new radiation machines have been implemented for routine treatment planning. Work is continuing on optimization of most of our computer programs on the VAX-11/750 system, from the old PDP 11/70 system. This work is, as before, complicated by the need for continuing reliable routine support for the clinical treatment. Great attention is continuing to be paid versatility, completeness and quality of documentation, as well as exchangeability. Generalization has progressed considerably by the introduction of patient representation by a density grid.